Factors influencing growth and ascocarp production in three species of Sporormiella

Abstract

Three species of Sporormiella (S. intermedia, S. isomera, and S. minima) grew and fruited over wide ranges of pH and temperature. The optimum pH was 7.0 or above and the optimum temperature range for S. intermedia and S. isomera was between 15 and 25 °C and for S. minima between 15 and 35 °C. Light did not affect either growth or fruiting. Ammonium acetate, D-alanine, and L-proline were excellent nitrogen sources for growth and fruiting. Several of the best utilized carbon sources were the following carbohydrates: monosaccharides: D(+)-xylose, D-glucose, fructose, and D-mannose; disaccharides: D(+)-cellobiose and maltose; polysaccharides: Alphacel, dextrin, and starch; sugar alcohols: mannitol and sorbitol. Growth increased linearly with an increase in the concentration of carbon from 1 to 8.0 g/ℓ. Sucrose was poorly utilized by S. intermedia and S. minima while S. isomera failed to utilize it entirely. None of the species studied utilized lactose. Alphacel yielded (at all concentrations) the maximum number of ascocarps. In the case of the other carbohydrates, S. intermedia and S. isomera produced the maximum number of ascocarps at very low concentrations of carbon (1.0 g/ℓ). Maximum production of ascocarps for S. minima was obtained with higher concentrations of carbon. Sporormiella isomera required an exogenous supply of thiamine for growth and ascocarp production while S. intermedia required both thiamine and biotin. Sporormiella minima grew with thiamine but fruited only with the addition of biotin to the medium. All three species grew well in basic synthetic liquid medium (Containing glucose as a carbon source and potassium nitrate as a nitrogen source) but none of them formed ascocarps.